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J. J. ZINN, OFALBION, PENNSYLVANIA.

Letters Patent No. 66,439, ma Juzg, 2, 18er.

IMPROVED MACHINE FOR FURROWING MILLSTONES.

TO ALL WHOM IT MAY CONCERN:

Beit known that I, J. J. ZINN, of Albion, in the county of Erie, and State of Plennsylvania, have inventedA a new and' improved Machine for Cracking or Furl-owing Millstones; and I dohereby declare that the following is a full, clear, 'and exact` description thereof, which will enable others skilled in the. art to make and use the same, reference being had to the accompanying drawings forming part of this specification, in which- Figure 1is a plan view of my improved furrowing machine, showing its application to a. millstone.

Figure 2 is a side view, partly in section, showing the same thing.

Similar letters of reference indicate like parts.

The object of this invention is to furnish millers with a machine for cracking the cross-furrows or channels of millstones with perfect regularity and accuracy, and great facility, without laying oiiA the furrows by measurements.

A is a heavy rectangular bed-plate, which lies flat upon the face of the millstone to be out, which is provided with an adjustable arm, B, secured to it at one end by a set-screw, a, and at the other end made concave, to it and bear against thespindle or-a block in the' eye of the stone, for the purpose of set-ting 'the bed-plate A in position. C C are short standards, placed at opposite edges, on one side of the bed-plate A, which support a round guide-rod, b, upon which is suspended a bent bar, c, that vibrates upon the. guide-rod b, and slides on the ba from one end to the other, when the machineis operated. The upper end of the bent bar c is made hollow, to receive the end of a pick-stock or handle,d,..which has a screw cut on it to screw back and forth as required inV the revolving nut e that is attachedftethe end of the bent bar c, as shown clearly in iig. 2. At the end of the handle or pick-stock d is a socketgfg, made Ttapering from the under side, to .receive the steel pick D, which fits. the taper and wedges itselt` in the socket suflioiently to work by the force of the blows made with it in cuttingthe furrows.

To work With-,this machine, the bed-plate A laid on the face of the stone with the en d of the arm B placed against the spindle, and the bed-plate is placed so that the guide-rod b shall be parallel with the crossfurrows to be made, as shown in red lines, iig.41. The pick D is set by meansof the revolving nut e at the right place for spacing and cutting the furrow; the operator then places himself upon the bed-plate A, and taking hold of the front bar c with his left hand, vand the pick-'handle d with his right hand, the pick is raised and struck with the right hand while the left hand moves the bar c back and forth on the guide-rod to cut the furrow straight.l Each set of furrows in the diierent quarters of the stone is thus cut straight and parallel to each other at'the required distances apart by screwing the handle d in or out of the hollow in the bar c, without moving the bed-plate Al till they are finished.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The vibrating-bar c, and the guide-bar b, combined with the bed-plate A, substantially as and for the purposes herein described.

2'. The vpick-handle d, with the taper-socket g, in combination with the nut e on the hollow end of the arm a, constructed and operating substantially as and for the purposes described.

JT. J. ZINN.

Witnesses z B. H. GALPIN, R. McNAMAn'A. 

